I just tried again and it looks like CashApp works on GrapheneOS now. I know I tried before and got blocked at the play integrity API step. It still does a play integrity API check but in a profile with play store and nerfed play services installed I was able to transfer cash in, buy sats, and send those sats out to another wallet. My apologies for misinformation earlier.

It wont let me login even though it installs. I have to use cash app on my normie phone i use for travel. I've tried it with both Google Play services installed and uninstalled.